Upstairs, almost any A&C or H&K (I'm guessing you are flying Y). I once paid the extra for the exit row pair which was very nice, however people tended to congregate in front of us and chat which grew a bit annoying after a while.
Check seatguru, apparently some of the window seats don't have a usable bin which would be a pain.
Can't help with advice on keeping away from children on the flight. If I knew the secret to that I would be selling the advice for a fortune on ebay.
I love this aircraft on SQ, it's a joy to travel even in economy.